sets.extras: adding adjoin-at*.

2013-10-10 09:53:04 -07:00 · 2013-10-10 09:53:04 -07:00 · 72edf36d7b
parent ed5582642b
commit 72edf36d7b
1 changed files with 3 additions and 0 deletions
--- a/extra/sets/extras/extras.factor
+++ b/extra/sets/extras/extras.factor
@ -25,3 +25,6 @@ IN: sets.extras
        accum over visited ?adjoin
        [ push ] [ remove-first! drop ] if
    ] each accum seq like ;
+
+: adjoin-at* ( value key assoc -- set )
+    [ [ HS{ } clone ] unless* [ adjoin ] keep dup ] change-at ;